jeffhergert
Thanks Jeff.
Elk Creek and Carnes sidings in the time table have manual interlockings at each end. They also show as having ABS between the switches, with no signals beyond. Part of the subdivision has ABS, the rest is dark as of the time table issue. I didn't look to see if there have been changes since it's issue.
On the Mason City Sub, it's TWC/ABS. They can issue after arrival warrants there because it's signalled territory. I think they can't, at least they stopped that practice a few years ago, and I haven't kept up on dark TWC territory. I don't know if the ABS island allows them to issue the after warrant.
Carnes is the siding they had that collision many years ago because of the way they were issueing warrants. A train was tied down on the main between the switches. IIRC, another train held two warrants. Both were "work betweens", one work between A and Carnes, the other work between Carnes and Z. Both warrants gave authority to the siding switches, but not authority on the main between the switches. The crew didn't catch that they needed to use the siding. The resulting collision spilled onto a crew van waiting to pick up a crew on another train. After this, they curtailled the use of "work between" warrants when a train didn't actually need the work between authority.
Jeff
jeffhergert While trains and engines don't need a warrant to occupy a siding, MOW/Signal needs to get a track permit. If a train or engine will be joint with MOW/Signal, then they need a track permit as well. One siding is located where there's a 3 track yard for the local that serves industries in the are, but not off the siding. The other siding is just that, no switches off of it. Jeff
While trains and engines don't need a warrant to occupy a siding, MOW/Signal needs to get a track permit. If a train or engine will be joint with MOW/Signal, then they need a track permit as well.
One siding is located where there's a 3 track yard for the local that serves industries in the are, but not off the siding. The other siding is just that, no switches off of it.
PTC offered a once-in-a-lifetime to put power switches in place in territory that couldn't otherwise justify the investment, at a relatively low MARGINAL cost. In other words, if you had to put in switch point monitors and broken rail detection, the additional cost of putting a power switch was lower than it would have been on pure dark track. On the other hand, there was also pressure not to let the already enormous cost of PTC grow out-of-hand either. I'm not surprised that different roads came up with different approaches.
The UP system you describe does more to aid train movement than the RCPS system I described (if your rules allow the DS to issue "After Arrival" warrants for meets at those sidings). It also costs more, so that's a trade-off someone made.
BUT what I DON'T understand is why they wouldn't call the track in between the switches CTC, or in other words why they require a warrant on the main line between switches. With control points (pardon me, "manual interlockings") at each end, with (I assume) signals at one end acting as distant signals for the other end, and a track circuit in between for broken rail protection, you have 95-99.9% of the equipment you would need to just have a CTC island. The only difference would be that, for a CTC island, any mainline switches between the siding switcheswould need electric locks in addition to the point protection that's already required for PTC.
Now, putting a track circuit on the siding could cause additional cost, especially if the siding has jointed rail, but would not be strictly necessary BNSF has (or at least used to have) numerous controlled sidings in CTC territory with no track circuits. This part probably looks quite similar to your sidings-between-manual-interlockings, but it technocally follows all the normal rules for CTC. MOW requires a track permit, trains need a joint permit to share track with MOW, but can otherwise enter the siding authorized by signal indication. Of course, the best indication they can ever get when going into the siding is "Restricting", since the signal system has no way of knowing if the siding is occupied.
But vive la difference, I guess.
Incidentally, the original implementation of ETMS (now called Legacy ETMS) that was implemented on one or two BNSF subdivisions included treating some or all of the TWC sidings as controller track. I can't tell you much about how that worked because I didn't ever deal with those territories, it was just something that we covered briefly in rules class. The legacy ETMS is now gone (replaced with i-ETMS and, in at least some places, with CTC) and we no longer have anything in our rulebooks about controlled TWC sidings.
One other question, out of curiosity: do you know if the sidings on the Worthington Sub work the same way, with manual interlockings at each end? I've driven past those a number of times, idly wondering how they worked.
Dan
dpeltier jeffhergert UP has started having the dispatchers control the siding switches at some sidings. While the signals look like CTC, they aren't. The switch and signals are considered to be manual interlockings. You need a track warrant to occupy the main track between stations and the main track between the siding switches, the manual interlockings. One crew found this out the hard way. They had a warrant up to the interlocking, but it didn't specify hold main track or clear main track at that station. The dispatcher lined them up down the main, gave them a signal but had not issued a track warrant to cover the move. They took the signal and went down the main to the interlocking at the other end of the siding. Jeff Interesting. On BNSF, where they have put in dispatcher controlled switches at the sidings, I believe it has been either RCPS switches in dark territory (see my previous post) or, in TWC / ABS territory, an "island" of CTC island that runs the whole length of the siding. Do they have a lot of industries that are switched from the siding? Or do they leave cars on the sidings on a regular basis? If so I suppose I could see why they might not want to install CTC and turn it into a "controlled" siding. On a CTC siding switching requires special conversations with the dispatcher, and derails have to be interlocked with the signal system. Dan
jeffhergert UP has started having the dispatchers control the siding switches at some sidings. While the signals look like CTC, they aren't. The switch and signals are considered to be manual interlockings. You need a track warrant to occupy the main track between stations and the main track between the siding switches, the manual interlockings. One crew found this out the hard way. They had a warrant up to the interlocking, but it didn't specify hold main track or clear main track at that station. The dispatcher lined them up down the main, gave them a signal but had not issued a track warrant to cover the move. They took the signal and went down the main to the interlocking at the other end of the siding. Jeff
UP has started having the dispatchers control the siding switches at some sidings. While the signals look like CTC, they aren't. The switch and signals are considered to be manual interlockings. You need a track warrant to occupy the main track between stations and the main track between the siding switches, the manual interlockings.
One crew found this out the hard way. They had a warrant up to the interlocking, but it didn't specify hold main track or clear main track at that station. The dispatcher lined them up down the main, gave them a signal but had not issued a track warrant to cover the move. They took the signal and went down the main to the interlocking at the other end of the siding.
Interesting. On BNSF, where they have put in dispatcher controlled switches at the sidings, I believe it has been either RCPS switches in dark territory (see my previous post) or, in TWC / ABS territory, an "island" of CTC island that runs the whole length of the siding.
Do they have a lot of industries that are switched from the siding? Or do they leave cars on the sidings on a regular basis? If so I suppose I could see why they might not want to install CTC and turn it into a "controlled" siding. On a CTC siding switching requires special conversations with the dispatcher, and derails have to be interlocked with the signal system.
Lithonia Operator dpeltier Here's what happens: before the dispatcher issues a track warrant over a given switch, he lines the switches for the route the train will take. In other words, he lines all of the switches within the warrant for the main line, except that if the train is supposed to clear the main line at the end of its limits, that last siding switch will be lined for the mainline. Did you perhaps mean to write:"if the train is supposed to clear the main line at the end of its limits, that last siding switch will NOT be lined for the mainline."?
dpeltier Here's what happens: before the dispatcher issues a track warrant over a given switch, he lines the switches for the route the train will take. In other words, he lines all of the switches within the warrant for the main line, except that if the train is supposed to clear the main line at the end of its limits, that last siding switch will be lined for the mainline.
Did you perhaps mean to write:"if the train is supposed to clear the main line at the end of its limits, that last siding switch will NOT be lined for the mainline."?
Why yes I did! Thank you, I have corrected it in the original post.
dpeltier Hills, MN is on the BNSF Marshall subdivision that runs southwest from Willmar, MN to Sioux City, IA. Along with the Sioux City subdivision (south from Sioux City to Ashland, NE), it is unsignaled track warrant control operation with PTC. However, these lines have an unusual feature at the siding switches called Remote Control Power Switches (RCPS). These are dispatcher-controlled power switches that physically are almost identical to a CTC power switch, but there are no controlling signals. Here's what happens: before the dispatcher issues a track warrant over a given switch, he lines the switches for the route the train will take. In other words, he lines all of the switches within the warrant for the main line, except that if the train is supposed to clear the main line at the end of its limits, that last siding switch will be lined for the mainline. The switches must be locked in the correct position for the CAD to issue the track warrant, and can't be unlocked until the warrant is released. This improved efficiency because only one train has to stop for a meet, and no one has to hand-line any switches. However, the system doesn't allow the dispatcher to issue "after arrival" warrants (and indeed BNSF practice is to avoid such warrants under most circumstances). In other words, Train A and Train B can't have warrants over the same piece of track at the same time (as they sometimes can if, for instance, the meet point is an "island" of CTC in the middle of TWC territory). So for a hypothetical meet at Hills: - The dispatcher lines the north siding switch at Hills for the siding, then issues a warrant to southbound Train to proceed south to NSS Hills and clear the main at that point. - Northbound Train B gets a warrant to proceednorth to NSS Hills and hold the main. - Let's assume Train A arrives before Train B. Train would go into the siding and clear it's warrant. The dispatcher would then line NSS Hills back to the main line, and issue a warrant to Train B to continue north. Assuming this warrant is issued before Train B arrives at NSS Hills, Train B never has to stop. - After Train B clears the south siding switch, they can roll up their warrant to that point. Then the DS would bend the SSS for the siding and issue a warrant to Train A to continue south. Look at this last step. How long it takes Train A to leave the siding is a function of how long it takes for Train B to roll-up its warrant and for Train A to get a new one. Even if the dispatcher is just sitting on the radio waiting for something to do (not likely), it takes time to go through the verbal song-and-dance routine needed to clear one warrant and issue another. What has changed recently is that the railroads have developed technology that allows them to deliver track warrants electronically to the PTC on-board computer. Now, Train B still has to verbally clear their warrant with the dispatcher (as I understand it) but once they've done that, the DS just has to line the switch over, get the warrant set up in CAD, and press a button to send it to Train A. So that could speed things up by a minute or two versus what you're used to seeing there. Incidentally, the colored lights you might see near the switch stands are position indicators, not train control signals. They're basically just a switch target that's easier to see from far away. They were added after the RCPS was originally rolled out because train crews wanted some visual verification that the switches were lined up for their route as they approached them at 49 MPH. So when you see one change color, it means that the DS has just lined the switch. Hope this helps, Dan
Hills, MN is on the BNSF Marshall subdivision that runs southwest from Willmar, MN to Sioux City, IA. Along with the Sioux City subdivision (south from Sioux City to Ashland, NE), it is unsignaled track warrant control operation with PTC.
However, these lines have an unusual feature at the siding switches called Remote Control Power Switches (RCPS). These are dispatcher-controlled power switches that physically are almost identical to a CTC power switch, but there are no controlling signals. Here's what happens: before the dispatcher issues a track warrant over a given switch, he lines the switches for the route the train will take. In other words, he lines all of the switches within the warrant for the main line, except that if the train is supposed to clear the main line at the end of its limits, that last siding switch will be lined for the mainline. The switches must be locked in the correct position for the CAD to issue the track warrant, and can't be unlocked until the warrant is released.
This improved efficiency because only one train has to stop for a meet, and no one has to hand-line any switches. However, the system doesn't allow the dispatcher to issue "after arrival" warrants (and indeed BNSF practice is to avoid such warrants under most circumstances). In other words, Train A and Train B can't have warrants over the same piece of track at the same time (as they sometimes can if, for instance, the meet point is an "island" of CTC in the middle of TWC territory).
So for a hypothetical meet at Hills:
- The dispatcher lines the north siding switch at Hills for the siding, then issues a warrant to southbound Train to proceed south to NSS Hills and clear the main at that point.
- Northbound Train B gets a warrant to proceednorth to NSS Hills and hold the main.
- Let's assume Train A arrives before Train B. Train would go into the siding and clear it's warrant. The dispatcher would then line NSS Hills back to the main line, and issue a warrant to Train B to continue north. Assuming this warrant is issued before Train B arrives at NSS Hills, Train B never has to stop.
- After Train B clears the south siding switch, they can roll up their warrant to that point. Then the DS would bend the SSS for the siding and issue a warrant to Train A to continue south.
Look at this last step. How long it takes Train A to leave the siding is a function of how long it takes for Train B to roll-up its warrant and for Train A to get a new one. Even if the dispatcher is just sitting on the radio waiting for something to do (not likely), it takes time to go through the verbal song-and-dance routine needed to clear one warrant and issue another.
What has changed recently is that the railroads have developed technology that allows them to deliver track warrants electronically to the PTC on-board computer. Now, Train B still has to verbally clear their warrant with the dispatcher (as I understand it) but once they've done that, the DS just has to line the switch over, get the warrant set up in CAD, and press a button to send it to Train A. So that could speed things up by a minute or two versus what you're used to seeing there.
Incidentally, the colored lights you might see near the switch stands are position indicators, not train control signals. They're basically just a switch target that's easier to see from far away. They were added after the RCPS was originally rolled out because train crews wanted some visual verification that the switches were lined up for their route as they approached them at 49 MPH. So when you see one change color, it means that the DS has just lined the switch.
Hope this helps,
Thanks to Chris / CopCarSS for my avatar.
Personally - I view having two separate menthods of control within one territory as being dangerous - for both the train & engine crews as well as the Train Dispatcher. Both crafts can find out things the hard way as potentially can the rest of the world via the media.
Never too old to have a happy childhood!
dpeltierHere's what happens: before the dispatcher issues a track warrant over a given switch, he lines the switches for the route the train will take. In other words, he lines all of the switches within the warrant for the main line, except that if the train is supposed to clear the main line at the end of its limits, that last siding switch will be lined for the mainline.
However, these lines have an unusual feature at the siding switches called Remote Control Power Switches (RCPS). These are dispatcher-controlled power switches that physically are almost identical to a CTC power switch, but there are no controlling signals. Here's what happens: before the dispatcher issues a track warrant over a given switch, he lines the switches for the route the train will take. In other words, he lines all of the switches within the warrant for the main line, except that if the train is supposed to clear the main line at the end of its limits, that last siding switch will be lined for the siding. The switches must be locked in the correct position for the CAD to issue the track warrant, and can't be unlocked until the warrant is released.
Before they started putting in the manual interlockings at the end of sidings on the Mason City Sub, all the sidings had spring switches at the south end. So the normal practice would be to have the southbounds go into the hole. Once in a while the dispatcher would do things differently, putting a northbound in the siding.
Normal practice for southbounds depended on how close the northbound to met was. If it was close, the SB conductor would line into the siding and get on the engine. The NB conductor would close the switch and go. Unless there were going to meet another SB. If it wasn't close the SB conductor would (depending on circumstances) usually line the switch back once in the clear and walk up to the head end.
SB trains left the sidings through the spring switch, so they didn't need to restore it. Putting a NB into the siding meant possibly walking the train twice. Once to enter the siding, once to leave the siding.
Spring switches in dark territory might also have a switch point indicator for facing point moves. Depending on what they use, a green or yellow light means the switch points are firmly (no gap) against the rail. Red or Lunar means the switch needs to be tested. Stop and flop. Stop the train, line the switch reverse and normal and see that the points fit properly.
In signalled territory, the block signals fulfill the switch point indicator roll. If the points aren't correct the circuit controller is supposed to shunt the signals, setting them red.
Murph, an anaolgy would be that if you run your finger along a freshly-milled piece of lumber with the grain, you won't get a splinter. But if you run your finger the opposite way, you almost certainly will pick up a splinter.
Think of a trailing-point move as going with the grain. The wheels push the points aside because they are facing the same direction the train is moving, so they can slide over to let the train pass. The wheels sort of wedge the points over from behind.
But, in the case of a facing-point move, the points ("splinters") are in charge. They are non-negotiable, and the train will always go the way the points dictate, period.
"Facing point move" and "trailing point move" refer to train movement direction, not switch movement.
So, as Balt said, let's say a train is doing a trailing point move (let's say out of a siding and onto the main, "running through" a spring switch lined for the main), but before the whole train has cleared the spring switch, the train backs up, or a lot of slack runs out rearward; cars that had come out of the siding will now back onto the main; the problem being that those cars are coupled to the rest of the train that is still in the siding. Something has to give. Big, bad splinter happens.
BaltACDthe signal system should be able to give a proceed signal to the train on the other track to TRAIL through the Spring Switch and then head out on Single Track; the points on the Spring Switch will remain lined for that route until the last car clears the switch at which time the points align for movement from Single track to #1 Track
A semi-automatic switch would stay open for the duration of the trailing move, but within the passage of the first car would have 'snapped' to the open position (even though the handle position wouldn't reflect that) and of course will remain in that open position whether or not the trailing move is reversed. Don't try a reverse even for a moment on a spring switch!
Murphy Siding Well, now I'm confusing myself. It almost looks like we're saying the same thing- almost.
Well, now I'm confusing myself. It almost looks like we're saying the same thing- almost.
Murph - you have to have a idea of the difference between 'Facing Point' and 'Trailing Point'. A Facing Point move will operate whichever way the points are lined
Lets say we are coming on Single track to the starting point of Double Track - the switch at the end of double track is a Facing Point switch for our movement. For the sake of argument the switch is lined to route our train to the right hand track which we will call #1 track. The End of Double Track Switch is a 'Spring Switch' in our example. We meet a train that is standing on the other track going in the opposite direction - when our train clears Single track and the Spring Switch - the signal system should be able to give a proceed signal to the train on the other track to TRAIL through the Spring Switch and then head out on Single Track; the points on the Spring Switch will remain lined for that route until the last car clears the switch at which time the points align for movement from Single track to #1 Track
https://www.youtube.com/watch?v=AzBjBUfX0gE
They creak a bit more, but it's not too noticeable over the usual racket of moving railroad equipment.
Semi-automatic switches have a noticeable 'snap' when lined by a locomotive or car.
Greetings from Alberta
-an Articulate Malcontent
I'm not sure I've ever seen or been unknowingly near a spring switch.
When a train "runs through" one, does it make a major racket, noise-wise? Seems like it would.
Murphy Siding blhanel Murphy Siding Any train going south ends up automatically being switched into the siding at Hills. The switch snaps back(?) after train goes through, lining the switch for northbound trains on the main. When the southbound train leaves the siding, that switch snaps back too, leaving the switch lined for the northbound trains as well. I would guess that they don't quite work that way, Murph. I would think the switch would stay in the preferred position until a train approaches it from the other track opposite of the switch points. The wheels of the train would force the switch points over, allowing the train to proceed through it. Anything coming from the point end would have to follow the alignment of the spring switch to whichever track it's normally aligned for. In your case, the south switch would "snap back" after the southbound left the siding, but the north switch wouldn't "snap back" until the northbound cleared it. Well, now I'm confusing myself. It almost looks like we're saying the same thing- almost. You're saying that the wheels of a a southbound train in my example would force the switch points over, allowing the train to proceed through it (and into the siding)? How does that happen?" In your case, the south switch would "snap back" after the southbound left the siding, but the north switch wouldn't "snap back" until the northbound cleared it." < The first part makes sense. Can you further explain the second part?
blhanel Murphy Siding Any train going south ends up automatically being switched into the siding at Hills. The switch snaps back(?) after train goes through, lining the switch for northbound trains on the main. When the southbound train leaves the siding, that switch snaps back too, leaving the switch lined for the northbound trains as well. I would guess that they don't quite work that way, Murph. I would think the switch would stay in the preferred position until a train approaches it from the other track opposite of the switch points. The wheels of the train would force the switch points over, allowing the train to proceed through it. Anything coming from the point end would have to follow the alignment of the spring switch to whichever track it's normally aligned for. In your case, the south switch would "snap back" after the southbound left the siding, but the north switch wouldn't "snap back" until the northbound cleared it.
Murphy Siding Any train going south ends up automatically being switched into the siding at Hills. The switch snaps back(?) after train goes through, lining the switch for northbound trains on the main. When the southbound train leaves the siding, that switch snaps back too, leaving the switch lined for the northbound trains as well.
Any train going south ends up automatically being switched into the siding at Hills. The switch snaps back(?) after train goes through, lining the switch for northbound trains on the main. When the southbound train leaves the siding, that switch snaps back too, leaving the switch lined for the northbound trains as well.
I would guess that they don't quite work that way, Murph. I would think the switch would stay in the preferred position until a train approaches it from the other track opposite of the switch points. The wheels of the train would force the switch points over, allowing the train to proceed through it. Anything coming from the point end would have to follow the alignment of the spring switch to whichever track it's normally aligned for. In your case, the south switch would "snap back" after the southbound left the siding, but the north switch wouldn't "snap back" until the northbound cleared it.
Well, now I'm confusing myself. It almost looks like we're saying the same thing- almost. You're saying that the wheels of a a southbound train in my example would force the switch points over, allowing the train to proceed through it (and into the siding)? How does that happen?" In your case, the south switch would "snap back" after the southbound left the siding, but the north switch wouldn't "snap back" until the northbound cleared it." < The first part makes sense. Can you further explain the second part?
Murph, I think you may be missing this basic point. Spring switches can only be "run through" by a train coming from the direction opposite the direction the switch points point; when that happens each wheel pushes the points over, allowing passage, but when the train is done passing through, the switch springs back to how it was to begin with.
Say you have a siding with a spring switch at each end, and the normal position for each is to be aligned for the main. Both southbound trains and northbound trains can leave the siding without changing the position of the switch; when either one runs through one, it springs back and realigns itself for the main. OTOH, neither southbound or northbound trains can enter the siding without re-lining the switch so as to be directed into the siding. Trains entering the siding are approaching (in this example of mine) from the side which the switch points point to.
I hope that's helpful.
And if I have this wrong, rest assured someone will correct me!
At least on one CTC installation, CPR (C stood for cheap) had a power switch at one end of each siding and a spring switch at the other. It saved a little bit of money, but meant that the dispatcher had no choice in which train took the hole at a meet. That was in the era when there were MoW personnel to keep the points clear of snow. That line is now mostly abandoned.
Both spring switches and semi-automatic switches (I have also heard them called rubber switches) do require more maintenance of the switch points. Where they still exist, the crews are now supposed to throw the switch manually before trailing through, but if somebody goofs at least the switch remains in good order.
John
CN used to put air wands on some locomotives to ease switch cleaning, they would be connected to the MR hose on one end. Then (predictably) someone got hurt somewhere, and they all got taken away.
We were never allowed to run through spring or semi-automatic switches when they are filled with snow/ice, but now we are not allowed to run through yard ones at all, this rule change coming about after a tank car ended up in two tracks at the same time (someone didn't shove an entire car through it before pulling back, like you are supposed to, I think a yardmaster or supervisor was watching the point via camera when this happened).
There are very few main track spring switches left out here, but they will all be equipped with heaters and are allowed to be run through.
Spring switches are identified by a round white sign with "SS" on it, and semi-automatic switches have diamond shaped targets instead of round or square ones.
Additional, unrelated switch info, if the handle is painted yellow then there is a derail nearby. If the handle is painted white the switch has a point clamp/lock.
mvlandsw If you try to spring it when it's full of snow or ice bad things may happen. Something has to give.
If you try to spring it when it's full of snow or ice bad things may happen. Something has to give.
Yeah - had a problem with a hand-throw once. Thought I could pull it through. You have no idea how hard the ice and snow will pack between the points and the stock rail... Especially when you discover there's no switch broom on the loco...
Larry Resident Microferroequinologist (at least at my house) Everyone goes home; Safety begins with you My Opinion. Standard Disclaimers Apply. No Expiration Date Come ride the rails with me! There's one thing about humility - the moment you think you've got it, you've lost it...
jeffhergert The LP would be for a switch heater.
Yeah - I knew that. The question would be why (aside from preventing the switch from freezing). Is it remotely controlled, or a spring switch, or just so the crews don't have to dig out the switch when it comes time to throw it?
A reconnaissance mission is in order...
zugmann BaltACD I fully believe that the 'run through' switches have been replaced by non-run through switches simply so more Efficiency Test Failures could be chalked up every measuring period by the Weed Weasels. Run-thru switches take maintenance. Can't have that. Won't you think of the stockholders? We'd rather have a crew run thru a switch, back up and make a huge mess that need Hulcher's. Becuase...it's....cheaper...?
BaltACD I fully believe that the 'run through' switches have been replaced by non-run through switches simply so more Efficiency Test Failures could be chalked up every measuring period by the Weed Weasels.
Run-thru switches take maintenance. Can't have that. Won't you think of the stockholders? We'd rather have a crew run thru a switch, back up and make a huge mess that need Hulcher's. Becuase...it's....cheaper...?
It also takes maintenance turn and/or replace the broken switch lug of a non-runthrough switch in addition to Hulcher charges. Have to keep those E-test failures coming!
Growing up in Cincinnati, I saw the streetcars use the Mt Adams incline. The double track street merged through a spring switch to a short stretch of single track which came to a trail and stay switch that led to the two approaches to the left and right inclined plane tracks with a similar arrangement at the other end of the inclined plane. So a down car would exit the plane and pass through the trail and stay switch to the single track leaving it lined for the next streetcar to head to the empty car. And the spring switch would put the down car on the outbound track. At the Fox River Trolley Museum, we use similar arrangements, Spring switchs on either end of a passing siding and trail and stay to return a car to the track it departed from if only operating one car at a time. If first car departs from the main, it trails throught the switch and when it returns it is directed to the main. When the next car leaves from track 2, it trails the switch and leaves it lined for track 2, so that when it returns, it goes to track 2. Of couse, on busy days when we run two cars and they pass on the siding, the returning car has to stop and thow the switch to get to the desired track.
If I remember from reading one of my hubby's books Techachapi for years had spring switches for almost its entire length of it where it had the sidings on it unless it had CTC control. If trains where going to meet one switch was always set for the main the other end was for the siding.
BaltACDI fully believe that the 'run through' switches have been replaced by non-run through switches simply so more Efficiency Test Failures could be chalked up every measuring period by the Weed Weasels.
It's been fun. But it isn't much fun anymore. Signing off for now.
The opinions expressed here represent my own and not those of my employer, any other railroad, company, or person.t fun any
jeffhergertThere are switches that can be lined by running through them (trailing point move) and they stay lined for the last route used. They are called "automatic" or "variable point" switches. We had one installed at Council Bluffs in the yard a few months ago. They, like spring switches, have signs or special switch targets to identify them. At one time many switches in yards (those for the bowl or classification tracks) were like that. Mostly those type are gone replaced by those that can't be run through. In some places, like in CB, they are making a limited come-back. Jeff
At one time many switches in yards (those for the bowl or classification tracks) were like that. Mostly those type are gone replaced by those that can't be run through. In some places, like in CB, they are making a limited come-back.
I fully believe that the 'run through' switches have been replaced by non-run through switches simply so more Efficiency Test Failures could be chalked up every measuring period by the Weed Weasels.
tree68 There is a common meeting place near me that I think has spring switches at both ends, or did at one time. Seems like I saw a picture of one of the switches with a "SS" sign at some point in the past. There are LP tanks at those points. Access to them isn't easy - maybe one of these days I'll see what I can find. I think I can get to at least one of them legally.
There is a common meeting place near me that I think has spring switches at both ends, or did at one time. Seems like I saw a picture of one of the switches with a "SS" sign at some point in the past.
There are LP tanks at those points.
Access to them isn't easy - maybe one of these days I'll see what I can find. I think I can get to at least one of them legally.
"S" or "S S" on a switch target is a spring switch. The LP would be for a switch heater.
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